<template>
  <div >
    <h1>当前求和为{{num}}</h1>
    <select v-model="n">
      <option :value="1">1</option>
      <option :value="2">2</option>
      <option :value="3">3</option>
    </select>
    <button @click="increment">+</button>
    <button @click="decrement">-</button>
    <button @click="incrementOdd">当前求和为奇数再加</button>
    <button @click="incerementWait">等一等再加</button>
  </div>
</template>

<script>
export default {
   name:'count',
   data() {
    return {
      n:1,
      num:0
    }
   },
   methods:{
    increment(){
       this.num += this.n
    },
    decrement(){
       this.num -= this.n
    },
    incrementOdd(){
       if(this.num % 2){
        this.num += this.n
       }
    },
    incerementWait(){
      setTimeout(() => {
        this.num += this.n
      }, 500);
    },
   }
}
</script>

<style>
button{
  margin-left: 5px;
}
</style>